Systems and methods for providing a sleeve reinforced subsea pressure vessel

ABSTRACT

A subsea vessel includes an outer layer of non-corrosive material and an inner layer of high-strength material that both corroborate in a subsea environment to withstand external pressure and prevent corrosion. The subsea vessel further includes a cavity surrounded by the inner layer and outer layer for providing storage in and protection from the subsea environment. The cavity is accessible via an opening that extends through the inner layer and the outer layer. The opening can be opened and closed with a cooperating cap that impermeably seals the cavity. The cap may include a number or connection mechanisms for being selectively secured to the opening. In addition, the cap may include a portion formed of a high-strength material and a portion formed of a non-corrosive material.

CROSS-REFERENCE TO RELATED APPLICATION

This U.S. patent application claims priority to and the benefit of U.S.provisional patent application No. 62/659,329, filed Apr. 18, 2018, theentire disclosure of which is incorporated herein.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a subsea vessel. More particularly, thepresent invention relates to subsea pressure vessel for withstandingexternal pressure and protecting against other environmental factorsfrom a subsea environment.

2. Related Art

This section provides background information related to the presentdisclosure which is not necessarily prior art.

Pressure vessels are containers used for a number of applications tomaintain an interior pressure different than that of ambient. Dependingon what a pressure vessel is storing and the ambient environment it willbe exposed to, pressure vessels are manufactured in a variety ofstructures and designs. Pressure vessels can be broadly categorized asinterior or exterior. Interior pressure vessels are commonly used forstoring gases or liquids at a pressure significantly higher thanambient. For example, common interior pressure vessels include certainresidential hot water heaters, air brakes, natural gas storage, fireextinguishers, and scuba cylinders, etc. Exterior pressure vessels, onthe other hand, contain an internal pressure that is significantly lessthan that of the environment. One common application for an exteriorpressure vessel is deployed in a subsea environment. For example, manyexterior pressure vessels are used for underwater applications such asinstrumentation housings, junction box housings, camera housings, etc.Unlike interior pressure vessels, exterior pressure vessels must bestructured to absorb external pressure, which increases as the pressurevessel is lowed deeper and deeper underwater. In addition, exteriorpressure vessels, particularly those used in salt water, must be able towithstand extremely corrosive environments. As such, corrosionsusceptible material cannot be used long-term as the integrity of theexternal pressure vessel will start to deteriorate via corrosion.Unfortunately, many of the most common and inexpensive materials thatare strong enough to withstand large external loads are also highlysusceptible to corrosion. For short term use, external pressure vesselsformed of aluminum with a surface that has been anodized have beensomewhat successful for short term use. However, the anodized surfacehas porosity and can easily be scratched, forming a spot that isvulnerable to being weakened by corrosion. For long term exposure,traditional methodologies have generally required using less common,more expensive high-strength and corrosion resistant materials.

Accordingly, there is a continuing desire to develop a pressure vesseland method of assembling same that is relatively simple in constructionand exhibits the benefits of being formed of high strength materialswithout requiring large amounts of expensive materials.

SUMMARY OF THE INVENTION

This section provides a general summary of the disclosure and should notbe interpreted as a complete and comprehensive listing of all theobjects, aspects, features and advantages associated with the presentdisclosure.

The subject invention provides a subsea vessel comprising at least onewall having an exterior surface and an interior surface. The at leastone wall forms an interior cavity that is defined by the interiorsurface, and the at least one wall further defines at least one openingfor providing access to the interior cavity. The at least one wallincludes an outer layer defining the exterior surface and an inner layerdefining the interior surface, wherein the outer layer comprises a firstmaterial that is corrosion resistant and the inner layer comprises asecond material that has a greater strength-to-weight ratio than that ofthe first material. A cap is included for sealing the at least oneopening from a subsea environment when the subsea vessel is immersed inthe subsea environment. The cap is removably attached to a portion ofthe at least one wall forming the at least one opening and includes asurface that, when in use, abuts the inner layer for withstanding a loadresulting from external pressure from the subsea environment.

The subject invention further provides a method of constructing a subseavessel comprising forming an inner layer having an interior surface andan outer surface about an interior cavity defined by the interiorsurface. The method proceeds by forming at least one opening with theinner layer, the at least one opening providing access to the interiorcavity and providing a bearing surface around the at least one opening.The bearing surface resides between the interior surface and the outersurface. The next step involves covering the outer surface of the innerlayer with an outer layer, wherein the outer layer comprises a firstmaterial that is corrosion resistant and the inner layer comprises asecond material that has a greater strength-to-weight ratio than that ofthe first material. The method further includes providing a cap forsealing the at least one opening from a subsea environment when thesubsea vessel is immersed in the subsea environment. The cap isremovably attached to a portion of the subsea vessel and includes asurface that when in use abuts the bearing surface for withstanding aload resulting from external pressure from the subsea environment.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purpose of illustration only and are not intended tolimit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and are not intended to limit the scope of thepresent disclosure. The inventive concepts associated with the presentdisclosure will be more readily understood by reference to the followingdescription in combination with the accompanying drawings wherein:

FIG. 1 is a perspective view of a first embodiment of a subsea vesselhaving a cylindrical body;

FIG. 2 is a perspective view of a first embodiment of a cap that sealsthe subsea vessel from an external environment;

FIG. 3 is a perspective view of a second embodiment the subsea vesselhaving a threaded cap;

FIG. 4 is a perspective view of a third embodiment of the subsea vesselhaving a first cap and a second cap;

FIGS. 5A through 5C are a series of cross-sectional views of additionalexample embodiments of the cap;

FIGS. 6A through 6C are a series of perspective views of additionalexample embodiments of the subsea vessel; and

FIG. 7 is a method flow chart including a number of steps inconstructing a subsea vessel in accordance with the subject disclosure.

DESCRIPTION OF THE ENABLING EMBODIMENT

Example embodiments will now be described more fully with reference tothe accompanying drawings. In general, the subject embodiments aredirected to a subsea vessel having an inner layer formed ofhigh-strength material and an outer layer that covers the inner layerand is formed of non-corrosive material. However, the exampleembodiments are only provided so that this disclosure will be thorough,and will fully convey the scope to those who are skilled in the art.Numerous specific details are set forth such as examples of specificcomponents, devices, and methods, to provide a thorough understanding ofembodiments of the present disclosure. It will be apparent to thoseskilled in the art that specific details need not be employed, thatexample embodiments may be embodied in many different forms and thatneither should be construed to limit the scope of the disclosure. Insome example embodiments, well-known processes, well-known devicestructures, and well-known technologies are not described in detail.

Referring to the Figures, wherein like numerals indicate correspondingparts throughout the views, the subsea vessel having a pair ofcooperating layers and method of constructing same is intended tosimplify construction and expense of traditional pressure vessels whilealso providing easy and repeated access to an interior cavity.

As illustrated in FIG. 1, a subsea vessel 20 includes a wall 22 formedof an inner layer 24 and an outer layer 26. As will be described ingreater detail below, the outer layer 26 comprises material that isnon-corrosive and the inner layer 24 comprises material that has agreater strength-to-weight ratio than that of the first material. Theouter layer 26 covers the inner layer 24 such that when the subseavessel 20 is submerged in salt water or any other corrosive environment,the outer layer 26 protects the inner layer 24 from corrosion and theinner layer 24 provides structural integrity to the subsea vessel towithstand a load resulting from external pressure. The wall 22 includesan interior surface 28 and an exterior surface 30, and the interiorsurface 28 forms an internal cavity 32 used as storage space. The wall22 further defines an opening 34 extending through the inner layer 24,the outer layer 26, and into the cavity 32 to provide access to thestorage space.

According to the example embodiment in FIG. 1, the subsea vessel 20 hasa cylindrical-shape extending between a first end 36 and a second end38. However, in other embodiments, the subsea vessel 20 can take othershapes, for example, a cylindrical, spherical, rectangular, ovular,elliptical, etc. In the present embodiment having the cylindrical shape,the inner layer 24 forms an inner cylinder 40 and the outer layer 26forms an outer cylinder 42. The outer cylinder 42 extends between thefirst end 36 and the second end 38 and the inner cylinder 40 is insetsuch that it extends between, but can be spaced from the first end 36and second end 38. While the first end 36 will generally define theopening 34, the second end 38 may define a second opening 44 similar tothat of the first 34. However, in an alternate embodiment, the secondend 38 may be permanently enclosed. As best illustrated in FIG. 2, theinner layer 24 forming the outer cylinder 42 may have an interiordiameter that is larger near the first end 36 and/or the second end 38to facilitate the initial insertion of the inner cylinder 40. Similarly,the inner cylinder 40 may have an outer diameter that is smaller nearthe first end 36 and/or the second end 38 to further facilitate theinitial insertion. In other words, in such arrangements, the innercylinder 40 may be pressed into the outer cylinder 42, until it islocated within the interior diameter between the first end 36 and thesecond end 38. In such arrangements, the inner diameter of the outerlayer 26 may be slightly smaller than the outer diameter of the innerlayer 24 so that the outer cylinder 42 is stretched outwardly andcompresses inwardly after insertion of the inner cylinder 40.

The opening 34 may be closed via a cap 46 partially shown in FIG. 2,which is removeably attachable thereto to impermeably seal the cavity 32from external factors like pressure. The cap 46 includes an interfacesurface 48 that, when in use, is pressed into some portion or bearingsurface of the inner layer 24. In other words, the cap 46 and opening 34are formed in such a way that external pressure acting inwardly iswithstood via contact between the inner layer 24, that compriseshigh-strength material, and the cap 46. Accordingly, it is preferablethat the cap 46 at least partially also comprises high-strength materialthat may be similar or the same as the inner layer 24 such that itdoesn't break upon introduction of high external pressure. In oneembodiment, the cap 46 includes an interior lining 50 of high strengthmaterial that is preferably shaped like the opening 34 but sized largersuch that it forms the interface surface 48 that abuts the inner layer24 bearing surface. In embodiments when the interior lining 50 comprisesthe same material as the inner layer 24, the interior lining 50 andinner layer 24 may have a similar to identical thickness. Furthermore,while the interior lining 50 is shown as being flat, it could be anyshape, including semi-spherical or hemi-spherical. As such, the layer ofhigh-strength material could be capsule-shaped for improved pressureresistance but the non-corrosive exterior may be cylindrical-shaped forimproved handling and storage when not in use. In addition, it ispreferable that the cap 46 further includes an exterior portion 52 thatcomprises non-corrosive material. At least one seal 54 is locatedbetween the exterior portion 52 and the interior lining 50. The seal 54could be an annular ring of elastomer material. In use, the cap 46 isplaced within the opening 34 and the interior lining 50 contacts theinner layer 24, the exterior portion 52 while the seal 54 prevents waterfrom coming into contact with the interior lining 50 and entering thecavity 32. While the cap 46 may be sized in such a way that it can bepress-fit into the opening 34, it is preferably that it is connected tothe wall 22 by additional mechanisms. For example, the cap 46illustrated in FIG. 2 is shown to include a flange 56 that extendsradially outward and at least partially aligns with the outer layer 26.The flange 56 and outer layer 26 may both further have cooperatingthreaded apertures 58 that can be drawn together with fasteners 60. Assuch, the fasteners 60 keep the cap 46 secured tightly against the innerlayer 24 until use wherein exterior pressure acting inwardly alsoprevents separation.

FIG. 3 illustrates a cap 62 in accordance with another embodiment of thesubject disclosure. The cap 62 includes a threaded body 64 that threadsdirectly into corresponding threads of the inner surface 24. Thethreaded body 64 may comprise a high-strength material, which may besimilar or identical to that of the inner layer 24. Like the previousembodiment, it is preferable that the cap 62 further includes anon-corrosive portion that prevents water from contacting thehigh-strength material.

FIG. 4 illustrates a pair of caps 66, 68 in accordance with yet anotherembodiment of the subject disclosure. More particularly, the pair ofcaps 66, 68 includes a first cap 66 and a second cap 68, the first cap66 having a first flange 70 and the second cap having a second flange72. A plurality of long fasteners 74 extend through the first flange 70and the second flange 72 and draw the caps 66, 68 towards the respectiveopenings 34, 44. The afore described fasteners could comprisehigh-strength non-corrosive material such as Titanium.

FIGS. 5A through 5C are a series of cross-sectional views of additionalexample embodiments of the cap. Referring first to FIG. 5A, the cap 76includes a lining 78 of high-strength material wherein the other portionof the cap is non-corrosive material. FIG. 5B is another embodiment ofthe cap 80 having a larger portion 82 formed of high-strength materialand a relocated seal 54 to prevent water from contacting thehigh-strength material. While not limited thereto, the embodimentillustrated in FIG. 5B could preferably include a treaded body aspreviously described in reference to FIG. 3 or other suitable closuremethods. FIG. 5C illustrates yet another embodiment of the cap 84 thatincludes a liner 86 of high-strength material that is at least partiallyspherical and preferably hemi-spherical for improved pressure resistancebut also has an otherwise flat exterior for improved handling andstorage. It should be appreciated, however, that the cap is not limitedto the above noted designs and materials. For example, the cap couldcompletely be constructed of the above noted high-strength,non-corrosive but expensive material. In addition, the cap could have adifferent locations and arrangements of seals 54, take various shapes tomate with openings having different profiles. In addition, the cap canhave a means to penetrate (FIG. 3) to allow for mounting an electrical,fiber-optic, or connection devices. In addition, in some embodiments,the cap may be permanently affixed to the subsea vessel.

FIGS. 6A through 6C are a series of perspective views of additionalexample embodiments of the subsea vessel. Starting with FIG. 6A, thesubsea vessel 88 is illustrated as being spherically-shaped. In FIG. 6B,the subsea vessel 90 is shown as a capsule-shape. In FIG. 6C the subseavessel 92 has a cubic-shape with tapered edges. It should beappreciated, however, that the subsea vessel could take many more shapesthan the above illustrated embodiments.

The subject disclosure further provides a method 200 of constructing asubsea vessel as illustrated in the flow chart in FIG. 7. Unlessotherwise stated, none of the steps of construction are limited to anyof the above example embodiments. The method 200 includes forming 202 aninner layer having an interior surface and an outer surface about aninterior cavity defined by the interior surface. Next, the method 200includes forming 204 at least one opening with the inner layer. The atleast one opening provides access to the interior cavity and the innerlayer further includes a bearing surface around the at least oneopening. The bearing surface resides between the interior surface andthe outer surface. The method 200 continues by covering 206 the outersurface of the inner layer with an outer layer, wherein the outer layercomprises a first material that is corrosion resistant and the innerlayer comprises a second material that has a greater strength-to-weightratio than that of the first material. Next, the method 200 includesproviding 208 a cap for sealing the at least one opening from a subseaenvironment when the subsea vessel is immersed in the subseaenvironment, the cap being removably attached to a portion of the subseavessel and including a surface that, when in use, abuts the bearingsurface for withstanding a load resulting from external pressure fromthe subsea environment.

The step of covering 206 the outer surface of the inner layer with theout layer can include molding 210 the outer layer over the inner layer.While not limited thereto, the molding 210 may include one or more ofcompression, extrusion, injection, and blow molding. Covering 206 theouter layer over the inner layer may also include welding 212 the outerlayer to the inner layer via any number of welding techniques including,but not limited to, inert gas, solid state, resistance, vibrational,etc. In addition, the covering 206 step may also include coating 214 theouter layer over the inner layer and allowing it to cure. In embodimentssimilar to that shown in FIGS. 1 and 2, the step of covering 206 mayfurther yet include a step of inserting 216 an inner layer into an outerlayer, wherein the inner and outer layers may be cylindrically-shaped.The covering 206 step may also include applying 218 adhesive on theinner layer and/or outer layer, contacting the inner layer and outerlayer, and allowing the adhesive to cure. Note that each of the steps ofcovering 206 the inner layer with the outer layer may further be appliedto the cap, wherein the cap includes a portion of high-strength materialand a portion of corrosion-resistant material.

Unless otherwise stated, the inner layer 24 and outer layer 26 are notlimited to any one materials or material combinations. However, in apreferred embodiment, the outer layer 26 is formed of a non-corrosivematerial and the inner layer is formed of a high-strength material. Thehigh-strength material could include one or more of Aluminum, Ceramic,Titanium, Copper-Beryllium, High-Strength Steel, Ceramic, Nickel Alloy,or additional metal alloys. If Aluminum is used, it may have an anodizedsurface before covering it with an outer layer. The non-corrosivematerial, on the other hand, could include one or more of Titanium,polyvinyl chloride (PVC), polyethylene (PE), polyurethane, epoxy with orwithout glass fibers or additional dielectric materials.

It should be appreciated that the foregoing description of theembodiments has been provided for purposes of illustration. In otherwords, the subject disclosure it is not intended to be exhaustive or tolimit the disclosure. Individual elements or features of a particularembodiment are generally not limited to that particular embodiment, but,where applicable, are interchangeable and can be used in a selectedembodiment, even if not specifically shown or described. The same mayalso be varies in many ways. Such variations are not to be regarded as adeparture from the disclosure, and all such modifications are intendedto be included within the scope of disclosure.

What is claimed is: 1) A subsea vessel, comprising: at least one wallhaving an exterior surface and an interior surface; the at least onewall forming an interior cavity defined by the interior surface, and theat least one wall further defining at least one opening for providingaccess to the interior cavity; the at least one wall including an outerlayer defining the exterior surface and an inner layer defining theinterior surface, wherein the outer layer comprises a first materialthat is corrosion resistant and the inner layer comprises a secondmaterial that has a greater strength-to-weight ratio than that of thefirst material; and a cap for sealing the at least one opening from asubsea environment when the subsea vessel is immersed in the subseaenvironment, the cap being removably attached to a portion of the atleast one wall forming the at least one opening and including a surfacethat when in use abuts the inner layer for withstanding a load resultingfrom external pressure from the subsea environment. 2) The subsea vesselaccording to claim 1, wherein the cap is removably attached to the outerlayer. 3) The subsea vessel according to claim 1, wherein the capincludes a flange that at least partially aligns with the outer layerwhen the surface abuts the inner layer. 4) The subsea vessel accordingto claim 3, further including at least one fastening member thatremovably connects the flange to the outer layer. 5) The subsea vesselaccording to claim 3, wherein the at least one opening has acircular-shape, and the cap includes at least one annular seal locatedbetween the flange and the surface that abuts the inner layer. 6) Thesubsea vessel according to claim 5, wherein the at least one walldefines a cylindrical shape extending axially between a first end and asecond end, and the at least one opening includes a first opening on thefirst end and a second opening on the second end. 7) The subsea vesselaccording to claim 6 further including a second cap for sealing thesecond opening, the second cap also being removably attached to theouter layer. 8) The subsea vessel according to claim 1, wherein the capincludes an exterior surface that at least partially comprises acorrosion resistant material, and the surface that when in use abuts theinner layer comprises a material that has a greater strength-to-weightratio than that of the corrosion resistant material on the exteriorsurface of the cap. 9) The subsea vessel according to claim 8, whereinthe corrosion resistant material on the exterior surface of the capcomprises the first material and the surface that when in use abuts theinner layer comprises the second material. 10) The subsea vesselaccording to claim 1, wherein the first material comprises at least oneof a dielectric material, a plastic, or a metal and the second materialcomprises at least one of a metal, a metal alloy, or a ceramic. 11) Thesubsea vessel according to claim 1, wherein the first material comprisesat least one of Titanium, polyvinyl chloride (PVC) or polyethylene (PE)and the second material comprises at least one of Aluminum, Titanium,Copper-Beryllium, High-Strength Steel, ceramic, or a Nickel Alloy. 12)The subsea vessel according to claim 1, wherein the at least one walldefines a spherical shape, a cylindrical shape, a rectangular shape, anoval shape, or an elliptical shape. 13) The subsea vessel according toclaim 1, wherein the at least one opening defines threads comprised ofthe second material, and the cap defines threads for connecting with thethreads in the at least one opening. 14) The subsea vessel according toclaim 7, further including at least one fastening member that extendsthrough the flange of the cap and a flange of the second cap, said atleast one fastening member drawing the cap and the second cap towardsone another to seal the subsea vessel. 15) A method of constructing asubsea vessel, comprising: forming an inner layer having an interiorsurface and an outer surface about an interior cavity defined by theinterior surface; forming at least one opening with the inner layer, theat least one opening providing access to the interior cavity andproviding a bearing surface around the at least one opening, the bearingsurface residing between the interior surface and the outer surface;covering the outer surface of the inner layer with an outer layer,wherein the outer layer comprises a first material that is corrosionresistant and the inner layer comprises a second material that has agreater strength-to-weight ratio than that of the first material; andproviding a cap for sealing the at least one opening from a subseaenvironment when the subsea vessel is immersed in the subseaenvironment, the cap being removably attached to a portion of the subseavessel and including a surface that when in use abuts the bearingsurface for withstanding a load resulting from external pressure fromthe subsea environment. 16) The method of constructing a subsea vesselaccording to claim 15, wherein covering the outer surface of the innerlayer with an outer layer includes molding the outer layer over theinner layer. 17) The method of constructing a subsea vessel according toclaim 15, wherein covering the outer surface of the inner layer with anouter layer includes welding the outer layer to the inner layer. 18) Themethod of constructing a subsea vessel according to claim 15, whereincovering the outer surface of the inner layer with an outer layerincludes coating the outer surface of the inner layer with the firstmaterial and allowing the first material to cure. 19) The method ofconstructing a subsea vessel according to claim 15, wherein the outerlayer defines an outer cylinder extending between a first outer layerend and a second outer layer end, and the inner layer defines an innercylinder extending between a first inner layer end and a second innerlayer end, and wherein covering the outer surface of the inner layerwith an outer layer includes inserting the inner cylinder into the outercylinder. 20) The method of constructing a subsea vessel according toclaim 19, wherein the outer layer has a first diameter between opposinginterior surfaces thereof that is larger than a second diameter betweenopposing interior surfaces thereof, the first diameter being locatednear at least one of the ends of the outer layer, thereby facilitatingguiding the insertion of the first inner layer end or the second innerlayer end. 21) The method of constructing a subsea vessel according toclaim 19, wherein the inner layer has a first diameter between opposingexterior surfaces thereof that is smaller than a second diameter betweenopposing exterior surfaces thereof, the first diameter being locatednear at least one of the ends of the inner layer, thereby facilitatingguiding the insertion of the first inner layer end or the second innerlayer end. 22) The method of constructing a subsea vessel according toclaim 19, further including applying an adhesive between the innercylinder and the outer cylinder and curing the adhesive. 23) The methodof constructing a subsea vessel according to claim 16, wherein moldingincludes molding the outer layer which comprises at least one ofTitanium, polyvinyl chloride (PVC), polyethylene (PE), dielectricmaterial, or corrosion resistant material over the inner layer whichcomprises at least one of Aluminum, Titanium, Copper-Beryllium,High-Strength Steel, Ceramic, Nickel Alloy, or other metals and metalalloys.